Derivative Instruments - Impact on Statements of Income, Net Investment Hedges (Details) - Net Investment Hedging - Foreign exchange - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Gains/(losses) recorded in income and other comprehensive income/(loss)
Amounts recorded in income	$ 21	$ (10)
Amounts recorded in OCI	$ (38)	$ (389)

Amount of gain (loss) from excluded component of derivative hedge, recognized in earnings. Excludes recognition under systematic and rational method.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 20
-Section 45
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109974929&loc=SL110061172-113977

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration